I can't comprehend VLANS and tagged/untagged

Port Tagging

Tagged: A vlan ID is assigned to a network port. All traffic going to and from that port is on the statically assigned vlan ID. If the port is tagged for vlan 20, then any traffic going to and from that port is on vlan 20.

Un-Tagged: No vlan ID's are assigned. Un-tagged can also be called Trunk or Access ports. Because an un-tagged port can pass traffic for multiple vlan's, when data is sent through this port the sending device must include a vlan ID so the switch knows where it's coming from and how to traverse it through to the destination. An un-tagged port can contain access to multiple vlan ID's. The ID's are set in the switch config.

Link: https://documentation.meraki.com/General\_Administration/Tools\_and\_Troubleshooting/Fundamentals\_of\_802.1Q\_VLAN\_Tagging#:\~:text=VLAN%2Denabled%20ports%20are%20generally,for%20only%20a%20single%20VLAN.

/r/sysadmin Thread